In the industrial field, various robots are widely used. For instance, in the field of processing semiconductors, a carrier robot is used in an apparatus for carrying substrates. This carrying apparatus constitutes one semiconductor processing equipment and serves as a front-end module for the semiconductor processing equipment, together with a plurality of semiconductor processing apparatuses respectively provided for performing different processes for the semiconductors.
FIG. 10 is an enlarged perspective view partly showing the carrier robot 1 in the related art, and FIG. 11 is a plan view of the carrier robot 1 shown in FIG. 10. This carrier robot 1 includes a base 2, and a lifting unit 3 provided to the base 2. Further, an arm 4 is attached to the lifting unit 3, such that this arm 4 can be lifted in the vertical direction as well as can be angularly displaced in the horizontal direction.
The arm 4 includes three connection members, i.e., a first connection member 5, a second connection member 6 and one robot hand 7. The first connection member 5 is attached to the lifting unit 3, such that this connection member 5 can be angularly displaced relative to the lifting unit 3. Further, the first connection member 5 is connected with the second connection member 6, and this second connection member 6 is further connected with the robot hand 7. In this case, the first connection member 5, second connection member 6 and robot hand 7 can be angularly displaced, respectively, relative to one another, about axes L1 to L3.
The carrier robot 1 constructed as described above further includes a control unit (not shown). This control unit serves to angularly displace the first connection member 5, second connection member 6 and robot hand 7, about the axes L1 to L3, while controlling the angle of each connection member 5, 6, 7. Namely, in this control unit, the angle in a zero posture of each connection member 5, 6, 7 upon shipment from a factory or the like is set in advance at 0 degree. Thereafter, the control unit serves to control each angle, about the axes L1 to L3, of the first connection member 5, second connection member 6 and robot hand 7, in order to change the posture of each connection member 5, 6, 7 into a desired posture, thereby moving the robot hand 7 to a desired position.
However, due to inadvertent or accidental collision between the arm 4 and other structures provided in each semiconductor processing apparatus and/or due to prolonged use of the carrier robot 1, each of the first connection member 5, second connection member 6 and robot hand 7 is sometimes angularly shifted from a correct position or angle about each corresponding axis L1 to L3. In such a case, even if the angle of each connection member 5, 6, 7 is set again at 0 degree, the connection member 5, 6 or 7 can no longer be returned to the zero posture. Therefore, in such a state, even if the control unit angularly displaces each connection member 5, 6, 7 by a predetermined angle, the robot hand 7 will be located in a position shifted from a predetermined position. To address this problem, it is necessary to adjust the zero posture of each connection member 5, 6, 7 to 0 degree. As the method for this adjustment, the so-called “zeroing method” has been known. This zeroing method is also used for adjusting the angle in the zero posture of each connection member 5, 6, 7 before the shipment from the factory to 0 degree.
As one example of the zeroing method, one approach using a jig pin 8 has been known. In the case of using this method, two through holes, for allowing the jig pin 8 to be inserted therein, are respectively provided to the first connection member 5 and second connection member 6. More specifically, when the first connection member 5 and second connection member 6 are angularly moved, respectively, by predetermined angles about the axis L2 from the zero postures thereof, the two through holes are in communication with each other, and thus the jig pin 8 can be inserted in such communicated two through holes. Further, a notched portion 9 is formed in the robot hand 7. In this case, when the second connection member 6 and robot hand 7 are angularly moved, respectively, by predetermined angles about the axis L3 from the zero postures thereof, the jig pin 8 can be in contact with the notched portion 9.
Namely, with the provision of such a jig pin 8 as described above, the angle of each connection member 5, 6, 7 relative to the zero posture thereof can be detected, and then each zero posture can be adjusted to 0 degree, based on the detected angle.